<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // f1();
        //变量定义
        var f1 = function(){
            console.log("i am f1");
        }
        f1();
        console.log("=====");

        var age = 7;

        // 立即执行函数，匿名
        // 减少变量污染
        // js，全局变量是魔鬼
        (function(){
            var blood = 100;
            console.log(111);
        }())
    </script>
</body>
</html>